Preparation And Surface Modification Of Photosensitive Polymer Microfluidic Chip

Microfluidic technology originated from the study of micro-electromechanical system(MEMS)in micro-fluid control.It was formed in the early 1990s.Through microfluidic technology,the complex chemical or biological analysis and synthesis process is integrated into a single chip to realize micrototal analysis system(vigiltas),or lab-on-a-chip.Up to now,the technology of microfluidic chip can be used in a variety of materials,such as glass,silicon,paper and a variety of polymers.Among them,photosensitive polymer has attracted much attention due to its rapid forming,low price and good corrosion resistance.In this paper,the low cost,fast microfluidic chip preparation,surface modification,bonding method and spontaneous flow of liquid in open chip based on photosensitive polymer were studied.The main contents are as follows:(1)Liquid mixing and spontaneous flow design with photosensitive polymer as microfluidic chip material.The s-type square wave enhancement mixed microchannel and the ordinary y-type dc channel mixed microchannel were designed,and the COMSOL simulation software was used to compare and analyze the mixing effect.The contact angle gradient microstructure was designed to simulate the droplet spontaneous flow through the tensile action of surface tension gradient.(2)Preparation of substrate based on photosensitive polymer microfluidic chip.SU-8,PDMS and PMMA are used to make male models,and the process parameters are determined.The inverting effect,inverting precision and inverting difficulty of the photosensitive polymer substrate were analyzed synthetically.Finally,PDMS is used as the positive model to prepare the substrate of the photosensitive polymer microfluidic chip.(3)Study on the surface modification technology of photosensitive polymer.The effects of process conditions,oxygen plasma and PVA surface coating on the hydrophilic and hydrophobic properties of the cured photosensitive polymer were investigated.Considering the factors of hydrophilic retention time and flexible control of surface contact Angle,the oxygen plasma method was used as the surface modification method of microchannel of microfluidic chip.(4)Research on bonding method based on photosensitive polymer microfluidic chip.Viscous polyester film and glass were used as the caps of photosensitive polymer microfluidic chips to determine the process flow and bonding methods,including viscous bonding,spin coating bonding and oxygen isoionic bonding,and the bonding strength was tested.(5)Application of photosensitive polymer microfluidic chip in droplet spontaneous flow.The size of the contact Angle was controlled by controlling the time of oxygen plasma treatment,and the contact Angle gradient was formed to control the spontaneous flow of liquid droplets,which was verified by experiments.